Behaviors to Reduce Heavy Metal Soil Contaminant Exposures among Community Gardeners Open Access

Hunter, Candis Mayweather (Spring 2019)

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Community gardens provide many benefits that should be balanced with possible risks of exposure to heavy metal soil contaminants in urban environments. Previous research has demonstrated that these risks may stem from the gardens’ proximity to heavily trafficked roadways, buildings with lead-based paint, and other environmental hazards. Behaviors can be implemented to reduce potential exposures; however, some gardeners may be unaware of risks related to contaminated soils and methods to mitigate exposure. Using an exploratory mixed-methods approach grounded in the Theory of Planned Behavior, (TPB) this study investigated factors that influence community gardeners to conduct behaviors to reduce their exposures to heavy metal soil contaminants.

The qualitative phase of this research utilized five focus groups to explore the behavioral, normative, and control beliefs related to soil testing, composting, mulching, and handwashing among Atlanta community garden leaders. Findings suggest that gardeners have varied risk perceptions of soil contaminants. Additionally, study results indicated that gardeners value heavy metal soil testing as a method to improve the soil quality and grow healthy food; however, perceived liability was a primary hindrance to testing. A key finding was that study participants did not associate composting and mulching as practices to reduce exposure to soil contaminants. Challenges regarding hand hygiene included concerns about decreased exposure to salubrious bacteria, inadequate access to potable water, and limited availability of gloves and wipes.

Using questionnaire data from 500 community gardeners across the United States, the second phase of the research applied logistic regression to examine factors that influence intention to soil test and hand wash after gardening. Results reveal that attitudes, subjective norms, perceived behavioral control, lower education and garden methods without pesticides were statistically significant predictors of soil testing and handwashing intention. Both qualitative and quantitative data reveal the following TPB themes: 1) In general, gardeners experience positive attitudes toward soil testing and handwashing; 2) Gardeners, government agencies, and nonprofit organizations are perceived to influence these behaviors; and 3) Gardeners experience lower perceived behavioral control for soil testing. Study findings have implications for interventions related to soil testing policy, exposure science research, and environmental justice initiatives.

Table of Contents

Chapter 1: Introductory Literature Review 1

Study Conceptual Framework: Theory of Planned Behavior 8

Study Significance: A Mixed Methods Approach 14

References 17

Chapter 2: A Qualitative Study of Atlanta Community Garden Leader Perspectives on Gardening Advantages, Heavy Metal Soil Contamination Risks, and Related Behaviors 24

Abstract 25

Introduction 25

Methods 29

Results 31

Discussion 38

Conclusion 41

References 46

Chapter 3: Safe Community Gardening Practices: Focus Groups with Atlanta, Georgia Garden Leaders 50

Abstract 50

Introduction 51

Methods 54

Results 56

Discussion 62

Conclusion 66

References 68

Chapter 4: Applying the Theory of Planned Behavior to Investigate Heavy Metal Soil Testing and Handwashing Intention Among Community Gardeners in the United States 76

Abstract 76

Introduction 77

Methods 80

Results 83

Discussion 85

Conclusion 90

References 92

Chapter 5: Summary & Conclusions 104

List of Figures

Figure 1.1: Theory of Planned Behavior 11

Figure 1.2 Study Conceptual Framework 16

Figure 3.1: Theory of Planned Behavior- Study Conceptual Framework for Soil Testing 45

Figure 4.1: Questionnaire Participant Community Garden locations 103

List of Tables

Table 1.1: Soil Screening Levels, Sources, and Health Effects for Lead, Arsenic and Cadmium 5

Table 2.1: Focus Group Participant Demographics 43

Table 2.2: Focus Group Participants' Community Garden Information 44

Table 3.1: Focus Group Participant Demographics 73

Table 3.2 Focus Group Participants’ Community Garden Information 74

Table 3.3: Summary of Participants’ Beliefs of the Safe Gardening Practices 75

Table 4.1: Demographic characteristics of the respondents and their community gardens 97

Table 4.2: Direct measures for Soil Testing and Handwashing Items 100

Table 4.3: Spearman correlations among TPB Variables 101

Table 4.4: Predictors of Soil Testing and Handwashing Intention 102

Table 5.1: Comparison of Qualitative and Quantitative Themes 119

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